Intermittent-grip device



s. s. MORTON.

INTERMITTENT GRIP DEVlCE.

APPLICATION FILED SEPT.Z5,1920.

Patented July 18, 1922.

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S S. MORTON.

INTERMITTENT GRIP DEVICE.

APPLICATION FILE D SEPT. 25, 1920.

1,423,007. Patented July 18, 1922.

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Zfi b/ .kE- 3 g stars rear INTERMITTE T-GRIP DEVICE.

Specification of Letters Patent. g mma; J l 18 1922 Application filedSeptember 25, 1920. Serial No. 412,739.

following to be a full, clear, and exact de-,

scription of the invention, such as will on able others skilled in theart to which it appertains tomake and use the same.

My invention relates to improvements in intermittent grip devices fordriving shafts and the like in a step by step manner, and the inventionhas more particular reference to a device of this character havinganoscillating motion.

This application forms a continuation in part of my United Statesapplication, Serial No. 323,709 filed Sept. 15, 1919.

One object of the invention is to provide an intermittent grip devicewhich may be set quickly and easily for driving a shaft or the like ineither direction, or set with equal facility in a neutral position atwhich no driving of the shaft will take place, even though the devicecontinues to oscillate.

In carrying out the above, a flexible friction band surrounds the drumor shaft to be driven and an oscillating lever is connected to the endsof said band for alternately contracting and releasing the latter.Before the device will operate in .thismanner, however, the hand must beinitially contracted by relatively canting the band and lever, and afurther object is to provide: yielding means for effecting this canting,without interfering with pro-per release of the band on the idle strokesof the lever.

Astill further object is to provide a device of the class set forth inwhich the flexible band is contracted by cam action and in which thestrengthwith which the shaft is gripped, is increased as thc resistanceto turning increases, thereby posltlvely war-ding against any slippageof the band on the shaft or drum.

Yet another object is toprovide anintermittent grip device which willbe. compara tively simple and inexpensive, yet absolutely positive inoperation, and one in which little wear will occur.

With the foregoing and minor objects in view, the invention resides inthe novel con struction and arrangement of parts hereinafter describedand claimed, the descriptive with a matter being supplemented by theaccompanying drawings. 7

Figure 1 is an elevation, partly in section, showing an intermittentgrip device constructed in accordance with my invention.

Figure 2 is a horizontal sectional view out principally on line 22 ofFig. '1, parts however being broken away and in section below this line.i

F igure'3 is a vertical sectional view with parts in elevation, showinga different position of parts from that disclosed in Fig. '1.

F igurew3 is a detail horizontal sectional view taken on line Zi -3 ofFig.

Figure 4 is a vertical transverse section as viewed on line 4.4c of Fig.1.

Figure 5 is a view in elevation showing.

metal links 5, 6 and 7, the link 7 being positioned between the innerends of the links 5 and 6 and pivoted thereto at 8. The inner sidesofall ofthe links, are curved for tight contact with the drum 2 and Iprovide means for loosely connecting the free ends of the links 5 and 6with each other and for fulcruming thelever 4; to the band. In thepresent showing, the link 5 is provided airof inwardly extending ears 9and the ink 6 is'formed with a similar ear 10 loosely received'betweensaid ears 9. All

of the ears 9 and 10 are slotted in a direction transverse to the axisof the drum 2 and for future reference I have given the slots of theears 9 the reference numerals 9 while 10" refers to the slot of the ear10. These slots loosely receive a fulcrum pinll by m'ean'sofwhich theoscillatory lever 4 is connected with the band 3. The inner end of thislever is provided with a T-head 12 whose center carries the fulcrum pin11 and whose ends are provided withrollers 13 or other appropriate shoeswhich engage cam surfaces 14 on the outer terminals 15 of the links 5and 6. 'The band is normally spread or opened to bring the shoes and camsurface into contact, by means of a coil spring or the like 16, theouter ends of the slots 9 and 10,thatis the ends adjacent the free endsof the ears 9 and 10, then receiving the fulcrum pin 11 as shown inFigs. 1 and 2. With the parts in this position, the lever 4 maybeoscillated without any turn ing effect whatever on the drum 2, since theband 3 is loose on the latter and will turn to and fro with said lever.By relatively canting the band and lever, however in either direction,said band is initially contracted or tightened upon the drum so that thefrictional contact thus created, will cause the lever 4 to tilt on thefulcrum 11 during any subsequent movement. Nhen the lever tilts in onedirection on the fulcruin 11, the band 3 is tightened and therebyrigidly grips and turns the drum 2, but

during the return motion of the lever, the band is loosened to someextent and turns freely on the drum. By forcing the inner end of thelever in one direction, transversely of the drum 2, the gripping deviceis set for rotating the drum clockwise, while forcing the end of thelever in the opposite direction will cause counter-clockwise rotation,and fOT'tllG purpose of effecting this shifting, I may provideany'appropriate means, two examples being given below.

In the form of construction shown in Figs. 1, 2 and 3, the T-head 12 isprovided with a laterally extending arm 20 having a roller or other shoe21 on its free end which is received in a curved guide 22 concentricwith the drum 2, said guide being carried by the end of a spring arm 23which is anchored at 24 to any suitable supporting structure 25. Betweenits ends, the spring arm 23 carries a stirrup 26 receiving a cam 27 on arock shaft 28 which may be turned at will by a suitable lever or thelike 29. l/Vhen the cam 27 is turned in one direction, the spring 23 andthe guide 23 are moved in the same direction, thereby shifting theT-head 12 transversely of the drum 2. mien the cam is turned in theopposite direction, however, said T-head is moved reversely. It willthus be seen that by properly actuating the lever 29, the grip devicemay be set for driving the drum 2 in either direction or for idling uponsaid drum.

In the form of construction shown in Fig. 5, the arm 20 is dispensedwith and a yielding lever 30 is fulcrumed near one end to the cross head12 of the lever 4, preferably upon the fulcrum pin 11 above described.At its inner end, the lever 30 is provided with a fork or otherappropriate bearing 31 which bears on the drum 2. Near the outer end ofthe lever 30, the lever 4 is provided with a series of, teeth 32 intoengagement with which said lever 30 may be" sprung.

this lever is moved in one direction, the T- head 12 is shifted in thecorresponding di rection, while reverse movement of the head may beeffected by shifting the lever 30 in the opposite direction. This levermay be held in either of its extreme positions or at a neutral positionby means of the teeth 32 and it will therefore be seen that by means ofsaid lever, the device may be set for idling or for driving eitherforwardly or rearwardly. Due to the resilient nature of the lever 30 andthe spring 23, slight movement of the inner end of the lever 4, transversely of the drum 2, as said lever alternately contracts and releasesthe band 3, is permitted and it will also be seen that the lever 4 is inno manner seriously resisted in its tilting upon the fulcrum pin 11.

As clearly shown in the several views, the T-head 12 ispreferablyconstructed of two metal plates secured to opposite sides ofthe lever 4 and the free ends of the links 5 and 6 are received betweensaid plates for cooperation with the shoes 13. flowever, although thisconstruction is preferred, it need not be followed in all instances.

Regardless of the exact details disclosed, the operation of the deviceis as follows: As long as the T-head 12 is held in a neutral position bymeans of the arm 20 and associated parts, or the lever 30, the band 3 isloose upon the drum 2 as shown in Figs. 1 and. 5- and hence said bandwill turn freely with any oscillation of the lever 4 and will produce nodriving of the drum. The moment that the band 3 and lever 4 arerelatively canted, however, in either direction, driving of the drumtakes place. In Fig. 3, the cam 27 has been operated, to cause thespring 23 and guide 22 to shift the T-head 12 to the left. This movementpulls the fulcrum pin 11 into tight contact with the outer ends of theslots 9 as shown in the detail sectional view, designated Fig. 3*. Atthe same time, the left hand shoe 13 is brought into contact with theadjacent cam surface 14, crowding the link 6 inwardly and contractingthe entire band 3 upon the drum 2. When the lever 4 now moves to theright, it will turn slightly upon the fulcrum pin 11 since the band 3 isnow frictionally gripping the drum 2. The moment this turning of pin 1.1takes place, the lefthand shoe 13 coacts with the cam surface 14 tocrowd the link 6 into still tighter contact with the drum. During thisaction, the fulcrum pin 11 draws to the left on the free end of the link5 and the latter is thus also tightly held against the drums The resultis that no slippage whatever of the band 3 takes place and the drum 2 ispositively turned in the direction of the arrow shown in Fig. 3. Whenthelever 4 moves on its return or idle stroke, that is to the left, theleft-hand shoe 13 rides down the cam surface 14- with which it waspreviously in contact, thereby releasing the grip of the band 3 on thedrum 2, with the result that said band returns to its initial. positionwithout moving the drum in a retrograde direction.

/Vhenever it is necessary to reverse the direc tion in which the drum 2is driven, the cam 27 is operated to throw the spring 23 to the right.The same operation as that above described then takes place, except thatthe right-hand shoe 13 and cam surface 14 come into play, and thefulcrum pin 11 pulls against the outer end of the slot 10 The devicewill therefore be operative when moving in the direction in which it waspreviously idle, and vice versa.

The operation of the form of construction shown in Fig. 5 is identicalwith that above set forth, the only difference between the two formsbeing in the manner of relatively canting the band 3 and the lever a.

From the foregoing, taken in connection with the accompanying drawings,it will be seen that I have devised a comparatively simple andinexpensive, yet a highly ellicient and in every way desirable,intermittent grip device. This device is usable wherever a ratchetmotion is necessary, for instance on the drum of a wire stretcher, inwhich instance the form of construction as shown in 5 is preferablyfollowed. Figs. 1, 2 and 3 illustrate the form of construction which ispreferably followed when adapting the invention to a transmissionmechanism, for instance on a tractor. In these views the numeral 25represents a portion of a transmission casing in which all of theworking parts may be located. lWhen the invention is used in thisconnection. the lever l is power driven, but this need not be enteredinto in detail in view of the fact that the present application isrestricted to the intermittent grip device, regardless of its use.

Since numerous changes may be made without departing from the spirit ofthe invention, as claimed, it will of course be understood that theaccompanying disclosure is for illustrative purposes only.

I claim:

1. In an intermittent grip device, a drum, a flexible band surroundingsaid drum, a band-contracting lever adapted to travel bodily along anarcuate path concentric with said drum, and means for positively cantingsaid lever, and band relatively before any travel of said lever alongsaid a-rcuate path, whereby to initially contract said band.

In an intermittent grip device, a drum, a flexible band surrounding saiddrum, a band-con'racting lever adapted to travel bodily along arcuatepath concentric with said drum, and spring means acting on said leverfor rocking the latter and positively contracting said band upon thedrum besaid lever, and means on said lever engag= ing one of said endsand cooperable with the aforesaid fulcrum in contracting the band on thedrum when the lever is'turned in one direction.

l. In an intermittent grip device, a drum,

a band surrounding said drum, a lever having one end positioned adjacentthe ends of the band, means loosely connecting said ends with each otherand forming a fulcrum for said. lever, one of said ends having a camsurface, and a shoe carriedby said lever at a point spaced from itsfulcrum, said shoe engaging said cam surface to crowd said one endinwardly and thereby contract the band, when the lever is turned in onedirection.

5. In an intermittent grip device, a drum, an oscillatory lever having aT-head at one end extending transversely of said shaft, a fulcrum pin atsubstantially the center of said T-head, shoes near theends of said T-head, a band surrounding the drum with its ends provided with openingsloosely receiving said fulcrum pin, said ends having cams contactingwith said shoes and acted on by the latter to contract the band forturning the drum in one direction or the other after said band has beeninitially contracted, and means for relatively canting said lever andsaid band to initially contract the latter for driving in eitherdirection.

6. In a transmission, a drum, a contractable band surrounding said drum,means for turning said band alternately in opposite directions, forcontracting said band around said drum when turning in one direction andfor releasing said band when turning in the other direction, and meansunder the control of the operator for positively contracting said bandinitially and for releasing said band independently of the bandoperating means.

7. In a transmission, a drum, a friction band surrounding said drum, afloating lever to which the ends of said. band are connected, means formoving said'lever bodily in a to and fro manner, a shoe carried'by saidlever and located at a point spaced laterally from its fulcrum, a curvedtrack concentric with said drum and in contact with said shoe, and meansfor shifting said track toward and, from said drum.

8. In a transmission, a drum, a friction band surrounding said drum, afloating lever to which the ends of said band are connected, means formoving said lever bodily in a to and fro manner, a shoe carried by saidlever and located at a point spaced laterally from its fulcrum, a curredtrack concentric with said drum and in contact with said shoe, a springconnected to said track, and means for moving said spring to shift saidtrack toward and from the drum.

9. In a transmission, a drum, a friction hand surrounding said drum, afloating lever to which the ends of said band are eonneoted, means formoving said lever bodily in ato and fro manner, a shoe carried by saidlever and located at a point spaced my hand.

SAMUEL STEPHEN MORTON.

